System and method for corneal pachymetry using plenoptic imaging

Abstract

Embodiments described herein provide improved systems and methods for corneal pachymetry. These systems and methods can be used to improve the accuracy of corneal measurements that are used for a wide variety of different ophthalmic procedures. One embodiment provides a system and method for corneal pachymetry using a plenoptic detector. For example, a corneal pachymetry system can comprise a light source, a plenoptic detector and a processing system coupled to the plenoptic detector. The light source is configured to illuminate the cornea of the eye, and the plenoptic detector is positioned at an angle relative to the eye. The plenoptic detector is configured to receive an image of the light source reflected from the cornea and generate plenoptic image data representing the images. The processing system is coupled to the plenoptic detector and is configured to analyze the plenoptic image data to accurately determine the corneal thickness of the eye.

What is claimed is: 
     
       1. A corneal pachymeter system, the corneal pachymeter system comprising:
 a light source configured to illuminate a cornea of an eye; 
 a plenoptic detector, the plenoptic detector positioned at an angle relative to the eye, the plenoptic detector configured to detect both intensity and direction of light of an image of the light source scattered from the cornea and generate plenoptic image data representing the image including both the intensity and the direction of the light detected by the plenoptic detector; and 
 a processing system coupled to the plenoptic detector, the processing system configured to:
 analyze the plenoptic image data to determine corneal thickness of the eye by computationally tilting the image of the light source derived from the plenoptic image data to more accurately correspond to a Scheimpflug orientation angle. 
 
 
     
     
       2. The system of  claim 1  wherein the plenoptic image detector comprises:
 a photosensor array, the photosensor array comprising a plurality of photosensors; and 
 a microlens array, the microlens array comprising a plurality of lenslets configured to direct the image to the photosensor array, the microlens array arranged a predetermined distance from the photosensor array. 
 
     
     
       3. The system of  claim 2  wherein the photosensor array comprises a two dimensional array of photosensors, and wherein the microlens array comprises a two dimensional array of lenslets. 
     
     
       4. The system of  claim 2  wherein the photosensor array is arranged in an image plane. 
     
     
       5. The system of  claim 2  wherein each lenslet in the microlens array receives light from the eye at different angles and spatially separates the light at different angles at the detector. 
     
     
       6. The system of  claim 2  wherein each lenslet in the microlens array is configured such that light arriving at a point in different directions is directed at a different point on the photosensor array such that direction information for light ray can be determined from a position of the light ray. 
     
     
       7. The system of  claim 1  wherein the light source is configured to output a slit shaped pattern of light. 
     
     
       8. The system of  claim 1  wherein the light source is configured change output position to scan over the eye. 
     
     
       9. The system of  claim 1  wherein the plenoptic detector is configured to rotate relative to the eye. 
     
     
       10. The system of  claim 1  wherein the light source is configured to change output position to scan over the eye and the plenoptic detector are configured to rotate relative to the eye. 
     
     
       11. The system of  claim 1  wherein the plenoptic detector is configured to change the angle relative to the eye. 
     
     
       12. The system of  claim 1  wherein the processing system is configured to analyze the plenoptic image data to determine corneal thickness of the eye by calculating distance to the cornea using the plenoptic data. 
     
     
       13. The system of  claim 12  wherein the processing system is configured to calculate the distance to the cornea using the plenoptic data by computationally focusing the image scattered from the cornea. 
     
     
       14. The system of  claim 12  wherein the processing system is configured to calculate the distance to the cornea using the plenoptic data by computationally focusing a virtual image that is scattered from an apex of the cornea. 
     
     
       15. The system of  claim 1  wherein the processing system is configured to analyze the plenoptic image data to determine corneal thickness of the eye by computationally tilting the plenoptic image data relative to the eye. 
     
     
       16. The system of  claim 1  wherein the processing system is configured to analyze the plenoptic image data to determine corneal thickness of the eye by computationally focusing the image of the light source scattered from the cornea of the eye. 
     
     
       17. The system of  claim 1  wherein the processing system is configured to analyze the plenoptic image data to determine corneal thickness of the eye by calculating corneal curvature by computationally focusing the image of the light source scattered from the corneal surfaces of the eye. 
     
     
       18. A corneal pachymeter system, the corneal pachymeter system comprising:
 a light source configured to output a slit of light to illuminate an eye and scatter an image of the light source from the cornea; 
 a plenoptic detector, the plenoptic detector positioned at an angle relative to the eye, the plenoptic detector configured to detect both intensity and direction of light of the scattered image of the light source and generate plenoptic image data representing the scattered image including both the intensity and the direction of the light detected by the plenoptic detector; and 
 a processing system coupled to the plenoptic detector, the processing system configured to analyze the plenoptic image data to:
 calculate distance to the cornea using the plenoptic data by computationally focusing a virtual image that is scattered from an apex of the cornea; 
 computationally tilting the image of the light source to more accurately correspond to a Scheimpflug orientation angle; 
 calculating corneal curvatures by computationally focusing the computationally tilted image of the light source; and 
 calculating a thickness of the cornea from the calculated distance to the cornea and the calculated corneal curvatures. 
 
 
     
     
       19. A method for determining thickness of a cornea in an eye, the method comprising:
 illuminating the cornea of the eye with a light source; 
 detecting both intensity and direction of light of an image of the light source scattered from the cornea with a plenoptic detector positioned at an angle relative to the eye; 
 generating plenoptic image data representing the image including both the intensity and the direction of the light detected by the plenoptic detector; and 
 analyzing the plenoptic image data to determine corneal thickness of the cornea by computationally tilting the image of the light source derived from the plenoptic image data to more accurately correspond to a Scheimpflug orientation angle. 
 
     
     
       20. The method of  claim 19  wherein the plenoptic image detector comprises:
 a photosensor array, the photosensor array comprising a plurality of photosensors; and 
 a microlens array, the microlens array comprising a plurality of lenslets configured to direct the image to the photosensor array, the microlens array arranged a predetermined distance from the photosensor array. 
 
     
     
       21. The method of  claim 20  wherein the photosensor array comprises a two dimensional array of photosensors, and wherein the microlens array comprises a two dimensional array of lenslets. 
     
     
       22. The method of  claim 20  wherein the photosensor array is arranged in an image plane. 
     
     
       23. The method of  claim 20  wherein each lenslet in the microlens array receives light from the eye at different angles and spatially separates the light at different angles at the detector. 
     
     
       24. The method of  claim 20  wherein each lenslet in the microlens array is configured such that light arriving at a point in different directions is directed at a different point on the photosensor array such that direction information for light ray can be determined from a position of the light ray. 
     
     
       25. The method of  claim 19  wherein the illuminating the cornea of the eye with a light source comprises illuminating the eye with a slit of light. 
     
     
       26. The method of  claim 19  further comprising rotating the plenoptic detector relative to the eye while illuminating the eye and receiving images of the light source scattered from corneal surfaces of the eye. 
     
     
       27. The method of  claim 19  further comprising changing output position to scan over the eye while receiving images of the light source scattered from corneal surfaces of the eye. 
     
     
       28. The method of  claim 19  wherein further comprising changing an angle of the plenoptic detector relative to the eye. 
     
     
       29. The method of  claim 19  wherein analyzing the plenoptic image data to determine corneal thickness of the eye comprises calculating distance to the cornea using the plenoptic data. 
     
     
       30. The method of  claim 19  wherein analyzing the plenoptic image data to determine corneal thickness of the eye comprises computationally focusing a virtual image that is scattered from an apex of the cornea. 
     
     
       31. The method of  claim 19  wherein analyzing the plenoptic image data to determine corneal thickness of the eye comprises computationally tilting the plenoptic image data relative to the eye. 
     
     
       32. The method of  claim 19  wherein analyzing the plenoptic image data to determine corneal thickness of the eye comprises computationally focusing the image of the light source scattered from the cornea. 
     
     
       33. The method of  claim 19  wherein analyzing the plenoptic image data to determine corneal thickness of the eye comprises calculating corneal curvature by computationally focusing the image of the light source scattered from the cornea.